New imaging analysis suggests that microvascular perfusion in the capillary bed, measured immediately after thrombectomy, can identify stroke patients who are likely to have poor recovery despite successful reopening of the large vessel. The study, presented at the American Society of Functional Neuroradiology meeting, focused on a measure called relative capillary transit time heterogeneity.
In 47 patients with anterior circulation large vessel occlusion who achieved complete or near-complete reperfusion, each 10% increase in this heterogeneity measure was associated with 1.4 times higher odds of infarct growth of at least 10 mL. The same measure also independently predicted poor 90-day functional outcome, defined as a modified Rankin Scale score over 2, with an odds ratio of 1.4 per 10% increase. By contrast, standard post-thrombectomy perfusion parameters such as cerebral blood flow and volume did not predict outcomes.
The researchers caution that the sample is small and the findings are proof of concept. They note that routine imaging is often done 24–48 hours after treatment, by which time other events such as late recanalization or early reocclusion may have occurred, whereas the immediate post-thrombectomy MRI may better reflect the state right after recanalization. If validated in a larger cohort, the microvascular measure could become a treatment target for the no-reflow phenomenon.